Enable all Android builders to use 'chrome_with_codecs'.

tools/mb/mb.py

Index: tools/mb/mb.py
diff --git a/tools/mb/mb.py b/tools/mb/mb.py
index 258df687cb30ce5f8e6aecca6471e57865919216..09c8ebcd833177a8ec97f612a55787ad7966bcb9 100755
--- a/tools/mb/mb.py
+++ b/tools/mb/mb.py
@@ -305,6 +305,28 @@ class MetaBuildWrapper(object):
       if not mixin in referenced_mixins:
         errs.append('Unreferenced mixin "%s".' % mixin)
 
+    # Check that 'chromium' bots which build public artifacts do not include
+    # the chrome_with_codecs 'mixin'.
+    if not 'chromium' in self.masters:
+      errs.append('Missing "chromium" master. Please update this proprietary '

[kjellander_chromium, 2016/03/15 03:54:59]

In WebRTC, we have own mb_config.pyl for the standalone build:
https://chromium.googlesource.com/external/webrtc/+/master/webrtc/build/mb_co...

This check causes an error when we run the mb.py validation on our config. Would
it be possible to just remove the error here?
It feels wrong that we would just add a fake 'chromium' master to our config.

+                  'codecs check with the name of the master responsible for '
+                  'public build artifacts.')
+    else:
+      for builder in self.masters['chromium']:
+        config = self.masters['chromium'][builder]
+        def RecurseMixins(current_mixin):
+          if current_mixin == 'chrome_with_codecs':
+            errs.append('Public artifact builder "%s" can not contain the '
+                        '"chrome_with_codecs" mixin.' % builder)
+            return
+          if not 'mixins' in self.mixins[current_mixin]:
+            return
+          for mixin in self.mixins[current_mixin]['mixins']:
+            RecurseMixins(mixin)
+
+        for mixin in self.configs[config]:
+          RecurseMixins(mixin)
+
     if errs:
       raise MBErr(('mb config file %s has problems:' % self.args.config_file) +
                     '\n  ' + '\n  '.join(errs))